Help with silver gelatin emulsion

[Juliano]

I’m having trouble to achieve good results with silver gelatin emulsion on sheets of paper.

I’d really appreciate if someone could help me find out what I may be doing wrong.

Here, I’ve created a flickr account to showcase some of my experiments.

Most of them has very low contrast and the coating is never regular.

I’ve made two emulsion samples (listed at the end of this topic). The second one was an attempt to increase the contrast. The prints were made with a enlarger in various times of exposure. I’ve also tested with three differents developers (Dektol, ID-14 and D8). Besides all of that, I tried to make some baryta coating too.

All of this information are present in the descripton of every piece on Flickr.

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Sample 1:

Solution A:

15 g gelatin

15 g potassium bromide

5 g NaCl

2 g citric acid (C6H8O7)

250 ml water

mix sol. at 50°C


Solution B:

12 g silver nitrate

100 ml water

raise temp. at 50°C


Sample 2:

Solution A:

40 g gelatin

16 g potassium bromide

250 ml water

mix sol. at 55°C


Solution B:

20 g silver nitrate

125ml water

raise temp. at 55°C


--


Thanks!

--

EDIT: The emulsion is unwashed and some of the prints has Sensitization (finishing).

 

[Sirius Glass]

Would you send photographs of them so that we can help evaluate them?

 

[dwross]

First, congrats on getting started making paper!
May I suggest here: http://www.thelightfarm.com/Map/TLFTutorials/tlftutorials-handmade-silver-gelatin-emulsions.htm
and here: https://www.blurb.com/books/6465389-the-light-farm
No paywalls, and hopefully all the recipes and coating information you need to get started. Coating silver gelatin emulsion on paper is just about the easiest alt process going.
Luck and fun,
d
www.thelightfarm.com

 

[Juliano]

Would you send photographs of them so that we can help evaluate them?

Here:
https://www.flickr.com/photos/157692676@N08/albums

I also edited the topic with a link. Sorry for that.

 

[Juliano]

First, congrats on getting started making paper!
May I suggest here: http://www.thelightfarm.com/Map/TLFTutorials/tlftutorials-handmade-silver-gelatin-emulsions.htm
and here: https://www.blurb.com/books/6465389-the-light-farm
No paywalls, and hopefully all the recipes and coating information you need to get started. Coating silver gelatin emulsion on paper is just about the easiest alt process going.
Luck and fun,
d
www.thelightfarm.com

wow Thanks for that!

 

[Photo Engineer]

To fix the problem, the addition times are needed as are the hold times after addition of AgNO3. It might be useful to add that Chloro Bromide emulsions are among the most difficult to make unless you are following someone's formula.

Also, what type of gelatin are you using?

PE

 

[Juliano]

To fix the problem, the addition times are needed as are the hold times after addition of AgNO3. It might be useful to add that Chloro Bromide emulsions are among the most difficult to make unless you are following someone's formula.

Also, what type of gelatin are you using?

PE

I'm using gelatin powder 180 bloom

The addition time of the respective samples:

Sample 1: 3 minutes
Sample 2: 10 minutes

Also, I readed on a blog that this paper is more suitable for contact print. Is it true?

Thanks!

 

[Photo Engineer]

What type of gelatin? From what source. Food gelatin often has additives. Is it bone or pig gelatin for example, and is it oxidized photo grade?

What is the hold time after addition?

And Silver Chloro-Bromides are very hard to control for speed and contrast. They can be made suitable for enlarging, but in this case, probably only for contact printing.

PE

 

[Juliano]

What type of gelatin? From what source. Food gelatin often has additives. Is it bone or pig gelatin for example, and is it oxidized photo grade?

It is pig gelatin and it is not oxidized photo grade.

What is the hold time after addition?

Usually 15 to 20 minutes. It should be long?

And Silver Chloro-Bromides are very hard to control for speed and contrast. They can be made suitable for enlarging, but in this case, probably only for contact printing.

Should I get rid of NaCl entirely?

 

[Photo Engineer]

Juliano, active pig gelatin is not the best choice for making an emulsion. At best, it is very difficult to work with. But, a 20 minute hold is probably good.

A pure bromide emulsion is going to be a lot faster than an Ag Cl/Br emulsion. But, they often turn out to be lower in contrast and less black in tone.

PE

 

[Juliano]

Juliano, active pig gelatin is not the best choice for making an emulsion. At best, it is very difficult to work with. But, a 20 minute hold is probably good.

A pure bromide emulsion is going to be a lot faster than an Ag Cl/Br emulsion. But, they often turn out to be lower in contrast and less black in tone.

PE

So, I researched and haven’t found a single place where I can buy photo-grade gelatin in Brazil. Do you know somewhere that I can import it from?


Is there a specific recipe for englarger use? What would it be?

 

[Photo Engineer]

Fotoimpex has some in Germany and Rousselot in France.

A formula would have to be worked out for your needs and condition, but try several web sites.

PE